From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 569C31991D3; Thu, 6 Jun 2024 14:21:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717683678; cv=none; b=IMb05PyXA3BqsBjOBMSbhCLAcbh5aIBTqJGJYk4nQFgo1d3mbVCJz6N35uyF1891T+n2JB1lF3iKViaSoUtNHfYBZxk23db9Gh2IZM3Hj4UuGO7mL8gv2TH23lw0r+HXVStuPOMnNeLyXSgZB6pJo99XU+pL+niaQZin4e2Rda4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717683678; c=relaxed/simple; bh=YePGCs4UfH2bEdac8AskEMe20QfTI2CPhe9/c/PpM5E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pQeumhXSzrzixiAXfXcLPgctNYqOvLZHNOSpD3WFRNQRc5Fg3shpmpI7d37vtJT5TLwvSpTgdkRIYfTZE3R5Yc7sI9yfCsgR1Dm+kwJSlV62kV017sfJiiXLomgjaEUuLyH5dJaijvYSzqnC7dtXgbBEHYi2akc7tv+bT/76i2c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AKYg2eG5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="AKYg2eG5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E350C32782; Thu, 6 Jun 2024 14:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1717683678; bh=YePGCs4UfH2bEdac8AskEMe20QfTI2CPhe9/c/PpM5E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AKYg2eG5QjPh2bE5Cezcj3oKq60kdpkfX1ni+pmK0CivuTZKxzs4nOtCOixwcLdkM 9gHlMXdQorAZLlYhTFAXXXw2qQccMBQ44ZAJ7Ay3o3aOYFbB+cfUK1HdlfrLSKZeta b/jXRPbmkdrn9+rUawnL9aEy8eEaLu9UdCwCZQWw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Roberto Sassu , Johannes Berg , Richard Weinberger , Sasha Levin Subject: [PATCH 6.6 577/744] um: Add winch to winch_handlers before registering winch IRQ Date: Thu, 6 Jun 2024 16:04:09 +0200 Message-ID: <20240606131750.964511788@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240606131732.440653204@linuxfoundation.org> References: <20240606131732.440653204@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Roberto Sassu [ Upstream commit a0fbbd36c156b9f7b2276871d499c9943dfe5101 ] Registering a winch IRQ is racy, an interrupt may occur before the winch is added to the winch_handlers list. If that happens, register_winch_irq() adds to that list a winch that is scheduled to be (or has already been) freed, causing a panic later in winch_cleanup(). Avoid the race by adding the winch to the winch_handlers list before registering the IRQ, and rolling back if um_request_irq() fails. Fixes: 42a359e31a0e ("uml: SIGIO support cleanup") Signed-off-by: Roberto Sassu Reviewed-by: Johannes Berg Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/drivers/line.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index b98545f3edb50..375200e9aba9a 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -673,24 +673,26 @@ void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port, goto cleanup; } - *winch = ((struct winch) { .list = LIST_HEAD_INIT(winch->list), - .fd = fd, + *winch = ((struct winch) { .fd = fd, .tty_fd = tty_fd, .pid = pid, .port = port, .stack = stack }); + spin_lock(&winch_handler_lock); + list_add(&winch->list, &winch_handlers); + spin_unlock(&winch_handler_lock); + if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt, IRQF_SHARED, "winch", winch) < 0) { printk(KERN_ERR "register_winch_irq - failed to register " "IRQ\n"); + spin_lock(&winch_handler_lock); + list_del(&winch->list); + spin_unlock(&winch_handler_lock); goto out_free; } - spin_lock(&winch_handler_lock); - list_add(&winch->list, &winch_handlers); - spin_unlock(&winch_handler_lock); - return; out_free: -- 2.43.0